A technique specialized in measuring a position and a direction in walking actions with use of self-contained sensors (such as an accelerometer, a gyro sensor, a magnetometer, and a pressure sensor) worn on a hip, a toe, and the like of a human is called pedestrian dead reckoning (PDR). As disclosed in Non-patent Literature 1, such a technique has conventionally been studied. In such a technique, real time tracking is carried out by sequentially updating a state vector of a moving body with use of a Kalman filter.